The present invention is directed toward a hair clamping device and more particularly toward such a device which is intended to hold a hank of hair being straightened or otherwise treated and which is extremely simple to utilize and easily and cheaply manufactured so that the same can be made to be disposable.
While the camp of the present invention may be used for various types of hair treatments such as tinting, frosting, selectively coloring, streaking, etc., it is particularly useful for straightening curly hair. Devices for straightening curly hair have been known for some time. Many prior art devices such as shown in U.S. Pat. Nos. 1,432,251; 1,986,689 and 2,419,117 utilize electric heating means to accomplish the straightening. While such devices may be somewhat effective in straightening the hair, they can also cause extensive damage to the hair because of the temperature and duration of the heat which must be applied in order to be effective. Furthermore, the cost of these devices is relatively high.
Other devices for use with chemical straightening of hair have also been proposed. Examples of these devices are shown in U.S. Pat. Nos. 2,955,604; 3,343,548 and 3,367,345. Insofar as Applicant can determine, the device shown in the first of these patents cannot be effective since means are not provided for maintaining the hair in a straight or tensioned condition during use. The latter two patents are useful only for straightening the portions of the hair adjacent the scalp. These devices cannot be used for straightening the entire length of the person's hair.
A wide variety of devices are also disclosed in the prior art for use in tinting or coloring hair. These are shown, for example, in U.S. Pat. Nos. 2,299,017; 2,299,018; 2,962,031 and 3,101,724. Such devices, however, are useful only for coloring or tinting and cannot be used for other purposes such as for straightening.
There is one prior art device which has been proposed specifically for use in dying hair at the roots but which could be used in a hair straightening process although there has been no previous suggestion for using the device in that manner. This device is shown in U.S. Pat. No. 3,662,767. The device of that patent is a box or cylindrically shaped hinged shell which carries a foam pad therein. The device is clamped around a hank of hair and is held in a closed position by a clasp mounted thereon. Because of the shape of these patented devices, only a limited number of them can be applied to a person's hair since they would otherwise interfere with each other. Furthermore, because of the shape of the ends of the devices, they cannot be placed too close to a person's head.
U.S. Pat. No. 4,671,302 which issued to the present Applicant describes a device which was intended to fill the gap left by the prior art devices described above. The prior patented device was directed toward a hair clamp which was specifically designed for straightening hair. It was comprised of an outer shell made of a sheet-like material such as cardboard or the like having its inner surface covered with a layer of foam material. The shell and the foam liner were folded over upon themselves along a mid-portion to form a clamp having front and back halves and a foam liner in the inside thereof. A separate U-shaped plastic clamp or plastic wire twist device was used to maintain the hair clamp in its closed position. The outer configuration of Applicant's prior patented hair clamp had a concavely curved bottom and a convexly curved top so that the same would fit closer to a person's head and so that a plurality of clamps could be stacked vertically on top of each other for longer hair.
While the device shown in Applicant's prior U.S. Pat. No. 4,671,302 had certain theoretical advantages over the prior art, it was not believed to be commercially practicable. The cardboard from which the shell was made was not rigid enough to hold the clamp in a tightly closed condition. This problem became even more pronounced when the device was in use and the cardboard was wetted by the straightening solution Furthermore, the single fold hinge put too much pressure on the foam at the hinge and relieved the force or pressure on the remaining surfaces of the foam. And finally, the tie lock used with the prior device was difficult to attach while the U-shaped clamp could easily be lost. As a result, Applicant's prior patented device was never commercially successful.